How can tartar and plaque be removed from teeth without grinding? is there any paste, etc. for it?
The girders of a suspension bridge form an arc. The definition of an arc is a curve or bowed shape, like a part of a circle. An example of an arc is a rainbow. To arc is defined as to make a curved shape or move in a curved path.
An arc is a portion of the circumference of a circle. In the figure above, the arc is the blue part of the circle. Strictly speaking, an arc could be a portion of some other curved shape, such as an ellipse, but it almost always refers to a circle. To avoid all possible mistake, it is sometimes called a circular arc.